After being forced to ground flights for much of the day after a technical problem with its reservation system, American Airlines is back in service, but expects continued delays and cancellations, the company said in a Facebook post.

The company said in the statement at 3:30 CDT that if passengers were already at the airport and had to travel Tuesday, they could rebook with another airline. If they had not yet arrived, they could rebook though American Airlines' reservation system or through another carrier, and the company would honor the difference.

The airline also said it would not charge for reservation changes, and would offer full refunds to anyone who chose not to fly today.

"It is important to note we see no evidence that today’s technical outage is related to the tragic events in Boston," the statement said.

The American Airlines reservation system, which operates more than 3,000 flights daily, suffered a complete outage earlier today. Here is the company's statement.

The Associated Press noted that American had canceled at least seven flights and was experiencing delays on more than 50 others.

FlightAware CEO Daniel Baker told CNBC that more than 100,000 people could be affected.